There are numerous applications in clinical medicine where a low cost, easy to use, and portable transcutaneous imaging system would be of great value. Ultrasound imaging may be uniquely suited to provide clear anatomic images of soft tissue and offer high temporal resolution, while being low-cost, easy to use, and reliable. While the role of ultrasound in the guidance of needle insertion into the venous system is well known, there is considerable scope for improvement and extension in this and similar, related applications. Specifically, our research is oriented towards achieving an order of magnitude cost reduction retaining reasonable image quality (particularly contrast), and developing the versatility to offer additional scan planes beyond those currently in common practice. More precisely, in addition to traditional B-Scans, we will provide C-Scans (image plane parallel to skin surface) using a highly integrated transducer array and beamformer. We hypothesize that adding the C-Scan capability will make our imaging system considerably easier to use by the less experienced user and therefore far more likely to be widely accepted. The Aims are: 1) Design, fabricate and test low-cost fully sampled 2D array. In order to form a C-Scan using a solid-state transducer device, it is necessary to employ a 2D transducer array. We have developed elegant solutions for realizing a highly integrated compact transducer array - beamformer pair that will produce the desired images at reduced cost and in a very compact space suitable for ubiquitous use in the clinic. 2) Develop and test efficient C-Mode beamforming and imaging algorithms New beamforming algorithms will be employed to form both C-Scan and B-Scan images. We will also develop novel compounding and flow estimation methods to take advantage of the fully sampled 2D array. 3) Design, fabricate, and integrate transmit and sampling electronics with 2D array A central contribution of the proposed work is a highly integrated small device (approximately the size of a calculator). This is achieved by integrating the electronics on special purpose ICs mounted adjacent to the array. 4) Quantify image quality and blood vessel visualization through phantom and in vivo experiments. We will perform realistic testing to validate the utility of the prototype device.